Shared Apple ID and Shared iMessages
My wife and I currently share the same Apple ID. Because of this we also get each others iMessages. Is there a way to turn off iMessage sharing or is it better to have two Apple IDs?
iPhone 5s, iOS 9.3.3
You could set up different Apple IDs for you and your wife and use family sharing.
Set up Family Sharing - Apple Support
Or maybe you could set up your Messages with another account, yahoo or gmail for example.